Yeah good idea - try and compare to what you can. I think the Arizona/Wentworth upstairs is fairly similar to the Sheridan 37/38.
FYI, we moved the downstairs wall at the back 500mm further out. That enabled an island bench (by shortening it a little) as well as making those rooms bigger. That was about $5k to do.
It was $930 for the 150mm high step. Hopefully it's high enough to get that tiered effect. It'll also depend somewhat on the height of the TV/projector screen.